Manufacture of nitrile compounds



Patented Apr. 6, 1943 UNITED STATES PATENT OFFICE MANUFACTURE OF NITRI'LE COMPOUNDS Walter Salzer and Hans Andersag, Wnppertal- Elberfeid, Germany, assignors to Winthrop Chemical Company, Inc., New York, N. Y., a

corporation of New York No Drawing. Application June 11, 1940, Serial No. 339,892. In Germany May 27, 1939 6 Claims.

This invention relates to a process of manufacturing nltrile compounds and the carboxylic acids formed by saponification oi the nitrile group of the said compounds.

In accordance with the present invention tertiary aminomethyl compounds, the tertiaryaminomethyl group of which has been formed by the action of formaldehyde and a secondary amine upon a com ound containing a. reactive hydrogen atom while replacing the said hydrogen atom, can be converted into the corresponding cyanomethyl compounds by reacting upon the said tertiary aminomethyl compound with hydrocyanic acid or a salt of hydrocyanie acid in the presence of a diluent which is inert tothe reacting components and at increased temperature. In this, process the tertiary amino group attached to the methyl group is replaced by the cyano group, while splitting off in the form of a secondary amine. Suitable compounds containing a tertiary aminomethyl group which has been formed by the action of formaldehyde and a secondary amine while replacing a reactive hydrogen atom for instance indol compounds, particularly those indol compounds which contains, the tertiary aminomethyl group in the 3-5'positiom Other suitable compounds of the kind'specifled are for instance aromatic hydroxyl compounds in which a reactive hydrogen atom "has been replaced by a tertiary aminomethyl group by the; action of formaldehyde and a secondary amine, for instance, dialkylaminomethyl phenols and dialkylaminomethylnaphthols. In the said compounds containing the tertiary aminomethyl substituent. the tertiary nitrogen atom may contain the most varied substituents. Tertiary aminomethyl groups derlved irom the lower aliphatic dialkyl anilnes are preferred sincesuch tertiary aminomethyl compounds are {host readily available, But also tertiary aniinomethyl.

compounds derived from other secondary amines, for instance from heterocyclic secondary amines, such as pyrrolidiri and .piperidine, may be used in the present process. The reaction is carried out in the presence of asolventor diluent which is inert to the starting materials such a water, alcohols, preferabhh water-soluble alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol which may be used in admixture with water, or also alcohols which are slightly soluble in water thalene, xylene, decahydronaphthalene, ligroine, chloroform, carbontetrachloride, dioxane etc. As salt of hydrocyanic acidswater-soluble salts are preferredfor instance, the ammonium salt and the alkali metaisalts such as the sodium, potassium and lithium salt. The alkaline reacting salts are particularly useful in alcoholic-aqueous solution. The nitrlle compounds primarily formed in such reaction mixture are simultaneously saponiiied to the corresponding carboxylic acids by the alkaline reaction of the mixture so that the tertiary aminomethyl compounds may be trans formed in this manner in only one step into the corresponding methyl carboxylic acids.

The invention may be performed, for instance.

' whileheating the mixture on the waterbath but such as amyl alcohol,,octy1 alcohol etc. Other solvents which are particularly useful when using hydrocyanic acid as the reacting agent are for instance, benzene, toluene, tetrahydronaphthereto:

higher temperatures such as from about 150-200" C. are advisable to accelerate the completion of the reaction. In such cases the reaction is advantageously carried out in a closed vessel which is capable of resistance to increased pressure.

The invention is furthermore illustrated by the following examples, without being restricted Example 1 grams of 3dimethylaminomethyl-indol are heated for some time with 300 com. of ethanol and a solution of 100 grams of sodium cyanide in ccm. of water in an autoclave at a temperature of 200 C. in the heating bath. The solution thus obtained is mixed with 200 com. of water and the ethanol is blown off with steam. After filtration the aqueous solution is acidified with diluted sulfuric acid until it reacts acid to Congo red. Thereupon the indoi-B-acetic acid formed precipitates in colorless crystals melting at 164- 165 C. The yield corresponds almost to that calculated theoretically.

Example 2 5 grams of 3-dimethylaminomethyldndol are heated with 10 grams of anhydrous hydrogen cyanide and 30 ccm. benzene for some time in an autoclave at a temperature of 150 C. in the heating bath. The solution is then mixed with aqueous sodium carbonate solution and the benzene layer is separated. After drying the latter with sodium sulfate the benzene is evaporated and the residue distilled. The indol-3-acetom'trile formed distils as an oil' at C. under 0.2 mm. pressure. By saponiflcation with alkali, the hitrile may be converted in the known manner into the corresponding carboxylic acid.

Example 3 grams of 3-piperidinomethyl-indol are treat ed with gram of anhydrous hydrogen cyanide and 30 com. of benzene according to the directions of Example 2. The indol-3-acetonitrile obtained distils as an oil at 160 C. under 0.2 mm. pressure.

Example 4 10 grams of 3diethylaminomethyl-indol are treated with 30 ccm. of ethanol and a solution of 10 grams of sodium cyanide in com. of water according to the directions of Example 1. The indol-3-acetic-acid melting at 164-465 C. is obtained.

Example 5 Example 6 10 grams of 1-hydroxy-Z-dimethylaminomethyl-4-methyl-benzene are heated for some time with 10 ccm. of ethanol, 5 grams of sodium cyanide and 10 com. of water in an autoclave to 150 C. The reaction mixture is then mixed with com. of water and the ethanol evaporated under diminished pressure....'l'he.aqueous solution is once extracted "with ether and then acidified by dilute sulfuric acid 'until the reaction is acid to Congo red. wrn'e 1-hydroxy-4-methyl-phenyl'-2- acetic acid thus precipitated is dissolved in ether, the solution is dried and the ether evaporated. The said acid is then obtained as a colorless oil which is readily soluble in aqueous alkali metalbicarbonate solution. The 1-methoxy-4-methylphenyl-2-acetic acid-methyl ester obtained by methylation boils at 120-125 C. under 5 mm.

pressure.

Example 7 10 grams of l-hydroxy-Z-dimethylaminomethyl-4-allyl-6-methoxy-benzene (obtained from eugenol, formaldehyde and dimethylamine) are heated for some time in an autoclavewith 10 com. of ethanol, 5 grams of sodium cyanide and p 10 com. of water to 150 C. The reaction mixture is treated as indicated in Example 6. The l-hydroxyi-allyl -6- methoxy phenyl -2- acetic acid is thus obtained in crystals melting at 92 C.

When using 1-hydroxy-Z-diethylaminomethyl- 4-allyl-6-methoxy-benzene (obtained from eugenol form aldehyde and diethylamine) the same final product is obtained.

Example 8 melting at 147 C.

When starting with 2',6-dihydroxy-1,5-bis-(dimethylaminomethyl) -naphthalene, the .2,6-dihydroxy-naphthalene( 1,5) di-acetic acid is ob-' Example 9 10 grams of 1-hydroxy-2-dimethylaminomethyl-4-methyl-6-bromobenzene (obtained from 1- hydroxyi-methyl-6-bromobenzene, formaldehyde and dimethylamine) are treated as indicated in Example 6 with 10 ccm. of ethanol, 5 grams of potassium cyanide and 10 ccm. of water. The l-hydroxyi methyl-6-bromophenyl-2-acetic acid is thus obtained in crystals melting at 83 C.

Example 10 10 grams of 5-dimethylaminomethyl-6-hydroxyquinoline (melting at 100 0., obtained from G-hydroxyquinoline, formaldehyde and dimethylamine) are treated with 10 ccm. of ethanol, 5 grams of sodium cyanide and 10 ccm. oi water as indicated in Example 6. The 6-hydroxyquinoline-5-acetic acid is obtained in crystals melting at 222 C.

Example 11 5 grams of 1-dimethylaminomethyl-2-hydroxynaphthalene are heated for some time with 5 grams of anhydrous hydrocyanic acid and 30 com. of benzene in an autoclave at 150 C. The reaction mixture is mixed with methylenechloride, the filtered solution twice washed with dilute hydrochloric acid, then dried and the solvent evaporated. The solid residue contains the 1' cyano-methyl-2-hydroxynaphthalene which may be converted into the Z-naphthol-l-aceticacid wherein X stands for a radical selected from the group consisting of the ,s-indole radical and the radical of a hydroxy aromatic compound, the

3 OH- group of which is in the same ring as the tained. When heated it decomposes at about: I.

270 C. The corresponding dilactone decomposes at 205 C.

CH2Y group, and Y stands for a secondary amino group with an alkali metal salt of hydrocyanic acid in the presence of a diluent which is inert to the reacting components and at increased temperature.

2. A process of preparing nitriles which com prises reacting upon an indol, substituted by a 3-tertiary amino methyl group with an alkali metal salt of hydrocyanic acid in the presence of a diluent which is inert to the reacting components at increased temperature. 1

3. The process of preparing nitriles which'comprises reacting upon an indol substituted in the 3-position by a tertiary aminomethyl group with an alkali metal salt of hydrocyanic acid in the presence of a diluent which is inert to the reacting components and at increased temperature.

4. The process of preparing nitriles and carboxylic acids therefrom which comprises reacting upon an indol substituted in the 3-position by a tertiary aminomethyl group with an alkali metal salt of hydrocyanic acid in the presence '01 water and a water-soluble alcohol and at increased temperature.

5. The. process oi. preparing nitriles which comprises reactins upon an aromatic hydroxyl compound the nucleus of which is substituted by a tertiary aminomethyl group, which has been formed by the action of formaldehyde and a secondary amine upon an aromatic hydroxyl compound containing a reactive hydrogen atom, with an alkali metal salt of hydrocyanic acid in the presence of a diluent which is inert to the reacting components and at increased temperature.

6. The process of preparing nitriles which comprises reacting upon a phenol the nucleus of which is substituted by a tertiary aminomethyl group, which has been formed by the action of formaldehyde and a. secondary amine upon an aromatic hydroxyl compound containing a reactive hydrogen atom, with an alkali metal salt of hydrocyanic acid in the presence of a diluent which is inert to the reacting components and at increased temperature.

WALTER. SALZER.

HANS ANDERSAG. 

